At the present time, electrical initiation of pyrotechnics, particularly those such as fireworks for the entertainment industry, is accomplished through the use of pyrotechnic igniters known as electric matches and sometimes referred to as electric igniters. The use of electric matches in a fireworks display allows the operator to initiate (i.e., ignite or fire) the pyrotechnics from a safe distance, and also affords the opportunity to synchronize the firing of pyrotechnics to a musical score through the use of automated, computer-generated firing commands.
Typically, these electric matches utilize a high resistance wire, most often Nichrome wire, which is attached by various means to the ends of two insulated copper conductor lead wires. The resistance wire is coated with a temperature sensitive pyrotechnic composition. When an electrical current is applied to the copper lead wires, the resistance wire (also known as a bridgewire), heats up to the ignition temperature of the pyrotechnic composition, thereby creating a flame.
Hot sparks and molten slag from the combustion by-products are projected outward, which, in turn, ignites another pyrotechnic device such as a display firework shell. Electric matches on the market today have serious safety issues, fatal accidents having occurred through their improper handling. These safety issues arise from the pyrotechnic mixtures utilized in electric match construction, the mixtures typically being sensitive to impact, friction, electrostatic discharge (ESD), stray electric currents, ground currents, and radio-frequency (RF) energy. It is common practice for manufacturers of electric matches to provide a plastic or rubber covering, known as a shroud, over the bulb of the pyrotechnic composition on the electric match to protect it from damage and accidental application of ignition stimuli.
Professional display fireworks typically utilize a quickmatch fuse, which comprises a thin paper tube of approximately three turns of paper covering an inner ignition core known as blackmatch. The blackmatch typically consists of several strands of cotton string which has been coated heavily with black powder in a suitable binder. In order to prepare the firework device for the attachment of an electric match, a technician typically makes an incision through the layers of paper on the quickmatch, thereby accessing the blackmatch core. The technician must then insert the electric match, with the protective shroud in place, into the quickmatch tubing adjacent to the blackmatch core. The incision is then covered with a length of masking tape. The lead wires from the electric match are folded over this piece of tape. Additional tape is then wrapped around the quickmatch, the lead wires folded over again, and then still more tape is wrapped over the folded lead wire and quickmatch tube, thereby securing the electric match within the quickmatch. This process forms a strain-relief for the electric match so that it is anchored to the quickmatch.
The previously described method is one of several methods commonly used for preparing the quickmatch for the electric match. All such techniques require a certain amount of skill on the part of the technician in order to successfully couple the quickmatch with the electric match. Several problems are known to occur when these techniques are practiced by unskilled technicians. For example, failure to function (i.e., the electric match does not ignite the blackmatch core of the quickmatch) will likely occur if the technician inserts the electric match between the folds of paper on the quickmatch such that the black powder core is not directly contacted. Another potential problem occurs when a quickmatch has a smaller than expected diameter. When this happens, the technician invariably removes the protective shroud on the electric match in order to insert it into the quickmatch tube, thus defeating the safety purposes for the shroud. This shroud removal substantially increases the risk of an accidental impact ignition of the electric match if firework shells happen to collide at this particular spot on the quickmatch, during shipping or handling, or if the firework shell is dropped on a hard surface.
Because of the technical skill needed as well as the amount of time required to correctly prepare the firework devices, attaching electric matches to leaders or fuses is typically performed at the fireworks plant. The electric match equipped devices are then stored at the plant until they are needed at a particular show location. While it is certainly safer to prepare the fireworks devices at the show location, this is typically not done due to the constraint of time and the need for experienced personnel to perform the work.
One attempt to solve the aforementioned problems is provided in U.S. Pat. No. 4,825,764 for CONNECTING DEVICE BETWEEN A FIRING FUSE OF A PYROTECHNIC PRODUCT AND AN IGNITER, issued May 2, 1989 to Marie-Jacques Jullien. The JULLIEN apparatus is designed to couple an electric igniter to the end of a fuse such as a quickmatch fuse. Proper assembly still requires preparation of the end of the quickmatch fuse and there is a high potential for misfiring of the pyrotechnic when the JULLIEN apparatus is used by an unskilled operator.
The present invention overcomes the shortcomings of these prior art procedures by providing an electric match/fuse coupling device designed to reduce or eliminate the foregoing safety issues and at the same time provide a method for quickly attaching an electric match to a quickmatch fuse by personnel of limited skill.